Integrated optic devices, often referred to as I/O chips, are used in optical systems such as optical interferometers and fiber optic gyroscopes, particularly for space vehicle guidance. A key to producing integrated optic devices on a commercial basis lies in the development of an inexpensive technique for aligning and attaching an optical fiber which will carry the light signal to a light port of the I/O chip. In the art of interfacing I/O chips with optical fibers, the act of coupling an optic fiber to the I/O chip is commonly referred to as "pigtailing".
One method for pigtailing an optical fiber to the light port of an I/O chip is disclosed and described in commonly assigned U.S Pat. No. 4,867,524. As disclosed therein, there is provided a fiber carrier having a V-shaped or semi-circular shaped axially elongated groove formed in its surface. The groove, which is uniform over its length, serves to support the end of the optical fiber to be coupled to the I/O chip. The fiber carrier is made of a material which has thermal expansion characteristics which are substantially the same as those of the I/O chip to which the optical fiber is to be coupled.
In coupling the optical fiber to the I/O chip, a metallic layer is deposited on both the fiber carrier and the I/O chip. The optical fiber is positioned in the axial groove in the fiber carrier with its tip disposed at the end plane of the fiber carrier and bonded thereto by any suitable metal joining technique such as laser welding, electrostatic welding, braising, soldering and diffusion welding. The fiber carrier is then disposed with the tip of the optical fiber it carries adjacent the light port of the I/O chip and the position of the fiber carrier adjusted until the light transfer and throughput between the I/O chip and the optical fiber is maximized by moving the fiber carrier in a plane normal to the axis of the groove in which the optical fiber is bonded, for example by rotating the fiber carrier with respect to the light port of the I/O chip until maximum light passes through the port. When the maximum transmittal of light is detected, the fiber carrier is welded to the I/O chip by any suitable metal joining technique such as those mentioned above with respect to the bonding of the optic fiber to the fiber carrier.
Although the method of pigtailing an optical fiber to an I/O chip disclosed in U.S. Pat. No. 4,867,524 is effective, it is labor and capital intensive. Additionally, the necessity of moving the fiber carrier in order to optimize alignment of the optic fiber to the light port of the I/O chip renders this method unsuitable for simultaneously positioning a multiplicity of closely spaced fibers at the light port of an I/O chip.
Accordingly, it is an object of the present invention to provide a method for positioning an optical fiber relative to an integrated optic device to which the tip at the end of the optical fiber is to be bonded wherein the necessity of moving the fiber carrier to align the optical fiber for maximum light transfer and throughput is eliminated.
It is a further object of the present invention to provide an inexpensive method for simultaneously positioning a multiplicity of optical fibers relative to an integrated optic device to which the tips at the end of the optical fibers are to be bonded.
Additionally, it is an object of the present invention to provide a fiber carrier for use in positioning one optical fiber or a multiplicity of optical fibers relative to an integrated optic device to which the tips at the end of the optical fibers are to be bonded without the necessity of moving the fiber carrier to align the optical fiber to maximize light transfer and throughput.